Urban Dictionary: nut up

v. To ejaculate. Literally, when one's testis climb to a "high & tight" position just before launch.

Al was about to nut up when her cell phone rang, turning his hard tool into a soft accessory.

by R2dad August 01, 2006

to take one for the team, against most odds, to guard closely (in athletic contests) commonly yelled at Ultimate Frisbee games

Yo Bill, nut up and be my wingman tonite

Nut up on that girl, she's been owning you all day

by Texas August 29, 2004

To "get high" or alter one's state of mind with drugs or alcohol.

I needs to nut up tonight. I be off tomorrow fo snizzle!
I'm bout to nut up punk.

by tmofft January 23, 2005

n. - an unfavorable or adverse situation

My teacher gave us detention - yo, that's the nut-up!

by "Cool Aaron" Taylor October 26, 2007